How to avoid password entry at start up ?

Open Administrative tools in control panel and go to Local security
policy.Select accounts and within that password policies. Set minimum
password length to 0. This should be enough to stop password from being
entered at startup.
I have received some criticism for asking users to set their password
length to 0 and I agree to some of the potential security risks. Here is
one better way to do it.

Go to START-RUN and enter "control userpasswords2" select the user the you
would like to have auto logon set to and then uncheck "Users must enter a
user name and password to use this computer". Ok out. Now you have to do
one more thing. Go to START-RUN and enter "control userpasswords" and
clicking on "Change the way users log on or off", and unchecking both "Use
the Welcome Screen" and "Use Fast User Switching".
Now Reboot and see it happen.
IMPORTANT DISCLAIMER: (Please make sure that you are doing this to user
account and not administrator account. If you do this to administrator
account or user accounts that have admin privileges and connect to
Internet. and do not have a good firewall installed or enabled, your are
exposing yourself to potential risks) XPTOOLS is not responsible for any
such damage. *Also note that default user accounts created by XP are in
admin group and have admin privileges so be careful.